The present invention generally relates to constant velocity joints and more particularly, to a vent for a constant velocity joint.
Constant velocity joints (CV joints) are common components in automotive vehicles. Typically, constant velocity joints are employed where transmission of a constant velocity rotary motion is desired or required. Common types of constant velocity joints are a plunging tripod, a fixed tripod, a plunging ball joint and a fixed ball joint. These types of joints currently are used in front wheel drive vehicles, or rear wheel drive vehicles and on the propeller shafts found in rear wheel drive, all wheel drive and four wheel drive vehicles. These constant velocity joints are generally grease lubricated for life and sealed by the use of sealing boots when used on drive shafts. Thus, constant velocity joints are sealed in order to retain grease inside the joint while keeping contaminants and foreign matter, such as dirt and water, out of the joint. To achieve this protection, the constant velocity joint is usually enclosed at the open end of the outer race by a sealing boot made of a rubber, thermoplastic, or silicone material. The opposite end of the outer race generally is enclosed by a dome or cap, known as a grease cap in the case of a disk type joint. A monoblock or integral stem and race design style does not use a grease cap, but is sealed by the internal geometry of the outer race. This sealing and protection of the constant velocity joint is necessary because contamination of the inner chamber may cause internal damage and destruction of the joint. Furthermore, once the inner chamber of the joint is lubricated, it is lubricated for life.
During operation, the constant velocity joint creates internal pressures in the inner chamber of the joint. These pressures have to be vented to the outer atmosphere in order to prevent pressure build-up which occurs during operation of the joint and may destroy the boot. If the pressure build-up is allowed to reach a critical state, the boot, protecting the joint from contaminants and water, may crack and deteriorate, or blow out, thus losing sealability. Generally speaking a constant velocity joint is usually vented by placing a small hole generally in the center of the grease cap or at least one hole around the outer periphery of the outer race. These prior methods of venting the gas are sometimes not adequate because if the constant velocity joint is in a static state and not rotating the lubricating grease may settle in the vent hole and block or hinder its function of venting any internal gas pressure. This type of vent may also allow the infiltration of contaminants. Once the internal pressure builds up the joint may fail due to a ruptured boot or other catastrophe. Furthermore, the constant velocity joint, after running for long periods of time, creates very high temperatures along with high pressures which are vented through the current vent holes. However, if the constant velocity joint is submerged or saturated in water or other contaminants, the water will, via vacuum, be sucked into the constant velocity joint, thus contaminating the grease lubricant and reducing the life of the constant velocity joint. Therefore, the ingress of water and other contaminants through the vent hole may reduce the life expectancy for the constant velocity joints.
Therefore, there is a need in the art for a constant velocity joint that will prevent the build up of internal gas pressure while eliminating the ingress of contaminants from entering the constant velocity joint.
One object of the present invention is to provide an improved constant velocity joint.
Another object of the present invention is to provide a new vent solution for a constant velocity joint.
Yet a further object of the present invention is to provide a vent for a constant velocity joint that has a permeable membrane that allows gas to pass through to the atmosphere.
Still a further object of the present invention is to prevent the entry of contaminants into the constant velocity joint internal chamber.
Yet a further object of the present invention is to provide a vent for a constant velocity joint that equalizes the difference in the internal and external pressures of the constant velocity joint.
To achieve the foregoing objects a constant velocity joint vent for use in a constant velocity joint is disclosed. The constant velocity joint vent includes a permeable membrane located within a chamber of the vent. The vent further includes a neck having a plurality of orifices thereabout, wherein the orifices allow gases to travel between an interior and exterior of the vent.
One advantage of the present invention is that the constant velocity joint includes a vent that has a permeable membrane to the atmosphere.
A further advantage of the present invention is that the constant velocity joint vent will allow gas, which is under pressure, to escape from the internal joint chamber to the atmosphere and will allow gas to enter from the atmosphere to the internal chamber thus creating an equalized pressure variant.
Still another advantage of the present invention is that the constant velocity joint will stop the entry of contaminants into the constant velocity joint.
Other objects, features and advantages of the present invention will become apparent from the subsequent description and appended claims, taken in conjunction with the accompanying drawings.